This invention relates to fuel-injected internal combustion engines and more particularly to apparatus for enriching the fuel supply to such an engine when starting under cold ambient conditions.
Various types of fuel injection systems for internal combustion engines are well known and widely used for both automotive and marine applications. One particularly novel system for use in marine environments is described in my co-pending application Ser. No. 151,623, now U.S. Pat. No. 4,349,000 entitled Control Means For Fuel Injection In An Internal Combustion Engine, filed May 20, 1980 which in turn is a continuation-in-part of my co-pending application, Ser. No. 120,467, now U.S. Pat. No. 4,305,351 entitled Two-Cycle Engine With Fuel Injection, filed Feb. 11, 1980.
Said co-pending application Ser. No. 120,467 is particularly described in connection with internal-combustion engines of the two-cycle variety, wherein fuel-injection is made directly into the crankcase region, and wherein certain economies and design simplifications are achievable through utilization of the same injector-control pulse to satisfy the injector requirements of a plurality of the cylinders of the engine. At the same time, particular pulse-width modulating circuitry is described for implementing the control of fuel injectors in such engines, with the control circuitry having application to engines other than those of the two-cycle variety.
Said co-pending application Ser. No. 151,623 now U.S. Pat. No. 4,349,000 addressed the problem of cold-start up and in particular considered this problem in the context of the different approach necessary in an outboard-marine application vis-a-vis the automatic-choke approach of the automotive industry. More specifically said co-pending application Ser. No. 151,623 now U.S. Pat. No. 4,349,000 provides means for automatically causing transient enrichment of fuel supplied to an engine, upon engine start-up. Said transient enrichment is also automatically reduced to zero in a matter of seconds, with the magnitude of the enrichment a function of sensed inlet manifold temperature at start-up.
Although said co-pending application Ser. No. 151,623 now U.S. Pat. No. 4,349,000 provided fuel enrichment to solve the problem of cold start-up for an internal combustion engine in an outboard-marine application, it did so only as a function of engine-starter switch activation. The instant invention also provides fuel enrichment as a function of engagement of the engine-starter switch but also considers throttle position when determining the amount and frequency of providing fuel enrichment at start-up. Reliance on both parameters, activation of the engine-starter switch and throttle position, provides a reliable and accurate system more adaptable to varying engine conditions and a system capable of maximum fuel enrichment at the critical time of engine start-up under cold ambient conditions.